{"slug":"public-domain-books-mystery","name":"Public-Domain Mystery Books: 50 With Checked Links","version":"1.0.0","updated_at":"2026-10-28T13:07:44.827Z","use_when":"Data catalog, not an instruction skill: 50 crime and detective books from Project Gutenberg, each with title, author, Gutenberg number, download count and an EPUB address that answered on 2026-10-28. Rights are the United States only. Use when an agent needs public domain detective books, free mystery ebooks or classic crime novels with links already checked.","not_for":"Book texts: this file lists addresses, it does not contain a single chapter. Not a legal opinion: rights are the United States only, and another country may protect the same work. Not a recommendation list, since rank is downloads. No audio books, no paper editions, no books after about 1930.","languages":["en"],"tags":["books","ebooks","epub","public-domain","project-gutenberg","mystery"],"category":"data","category_url":"https://aiskills402.com/categories/data","keywords":["public domain detective books","free mystery ebooks","classic crime novels"],"faq":[{"q":"Which detective stories lead the list?","a":"The Adventures of Sherlock Holmes, Dracula, The strange case of Dr. Jekyll and Mr. Hyde. Rank follows the download count kept by Project Gutenberg's public API, read on 27 and 28 October 2026, so it changes slowly but does change."},{"q":"Can a shop sell these crime novels as paid ebooks?","a":"This file does not answer that. It records only that Project Gutenberg marks each work as out of copyright for US readers, and that the gutenberg.org address returned an EPUB. Selling is your own legal question, and so is any other country."},{"q":"How many mystery entries had a dead address?","a":"None. All 50 entries answered with a zip-based EPUB archive on 2026-10-28. The check requests only the first kilobyte of each file, so it proves the address is alive, not that every chapter is intact."},{"q":"Does the detective list say which novel to read first?","a":"It does not. A reader who wants a starting point among series characters must look elsewhere; the file only orders by downloads and never judges plot, period or difficulty. Series order, spoilers and the quality of a translation are equally outside it."}],"examples":[{"lang":"en","model":"claude-sonnet-5-5","input_excerpt":"Which book is number 1 in the catalog?","output_excerpt":"Number 1 in the catalog is **The Adventures of Sherlock Holmes** by Arthur Conan Doyle (Gutenberg #1661, 96,353 downloads).\n\nEPUB: https://www.gutenberg.org/ebooks/1661.epub3.images\n\nThe link answered with an EPUB file when checked on 2026-10-28. Rights are public domain in the United States only."}],"page_url":"https://aiskills402.com/skills/public-domain-books-mystery","markdown_url":"https://aiskills402.com/skills/public-domain-books-mystery.md","image_url":"https://cdn.aiskills402.com/og/skills/public-domain-books-mystery/77ff768e.png","related_url":"https://api.aiskills402.com/v1/skills/public-domain-books-mystery/related","purchases_count":null,"tested":{"date":"2026-10-28","strong":{"model":"claude-sonnet-5-5 (Claude Code alias \"sonnet\")","verdict":"Answered all 10 questions about the detective and crime books list correctly from the file: the first title, a mid-list Gutenberg number, the exact addresses of the last and a middle book, the download count of number five and the first three titles of the busiest author. Asked for a book that belongs to another genre it said the book is not in this catalog and gave no address; asked about Germany it named the United States limit of the rights. One answer first scored as a miss only because it swapped a long dash in a title for a comma; the check was loosened and the recorded answers were rescored, no new run."},"weak":{"model":"claude-haiku-5-5 (Claude Code alias \"haiku\")","verdict":"Also answered all 10 questions, with shorter replies. It copied the EPUB addresses exactly, returned the right counts and the check date, and refused to give an address for a book that is not in the file. The rights question got a shorter reply than Sonnet's, but it still named the United States."},"note":"10 questions built from the file itself: first title, a Gutenberg number, two exact EPUB addresses, a count of books, the check date, a download count, the busiest author's books, a book that is not in the catalog and the rights outside the United States. Checks are exact strings or one regular expression each. One run per model and question. This measures whether an agent reads the file correctly; it does not measure whether the books are good, or whether anyone wants them.","report_url":null},"price_usd":"0.10","price_micro":100000,"size_bytes":10925,"sha256":"61cab62efc5bead91440ea0d214ae014c7071d9254d008bae4daf49b41c91873","outline":["What was checked","Rules for the agent that reads this file","The 50 books"],"license":{"summary":"Perpetual, non-exclusive; use and modify for yourself incl. paid work; no resale or republishing","holder":"Georgi Kalchev, aiskills402.com","url":"https://aiskills402.com/docs#license"},"buy_url":"https://api.aiskills402.com/v1/skills/public-domain-books-mystery/file","redownload_url_template":"https://api.aiskills402.com/v1/purchases/{token}","mcp_tool":null,"payment":{"protocol":"x402","scheme":"exact","asset":"USDC","selling":true,"network":"base","network_caip2":"eip155:8453","pay_to":"0x8e37022edcf0f21cf3c9f93fee9d4d32519f36f4","facilitator":"cdp"},"seo_title":"Mystery Books: 50 Checked EPUB Links","seo_description":"Fifty detective and crime classics led by The Adventures of Sherlock Holmes, whose EPUB addresses were tested on 2026-10-28. A single $0.10 purchase.","versions":[{"version":"1.0.0","date":"2026-10-28","changelog":"# Changelog\n\n## 1.0.0 — 2026-10-28\n\nFirst release: 50 crime and detective books with title, author, Gutenberg number, download count and EPUB address. All 50 addresses answered with an EPUB archive on 2026-10-28. Rights are the United States only. Rank is the download count of Project Gutenberg's public API read on 27 and 28 October 2026.\nPrice: $0.10; the value is the checking and the ordering, not the books.\n"}]}